Can temperature gauge be adjusted?

[saxart]

This past summer I was driving down the road and started hearing a fast ticking noise from somewhere inside the cab. Long story short, it was the temp gauge. The needle was slamming from high to low over and over and over until I pulled over, popped the hood and found that the temp gauge wire had disconnected itself from the sensor and was grounding out on the engine block.

After reconnecting the wire, the gauge now reads very low even when the engine is up to operating temp.



Is there a way to adjust these gauges so it reads at the right spot when the engine is warm, or do I need to replace the original gauge?

[68 C10 Driver]

As inexpensive as the gauges are, I would just replace it.

[Accelo]

A lot of people add resistance to the sensor wire to "re-calibrate" the gauge. It only works when the gauge reads high. I suspect the wild gyrations moved the needle on the stem.
Least expensive option will likely be replacing the gauge as 68 recommended.

[Palf70Step]

Make sure your sending unit is good before you do the gauge. IT's a cheaper fix to begin with.

[Steeveedee]

Originally Posted by Accelo

A lot of people add resistance to the sensor wire to "re-calibrate" the gauge. It only works when the gauge reads high. I suspect the wild gyrations moved the needle on the stem.
Least expensive option will likely be replacing the gauge as 68 recommended.

Bolding mine. This.

[Accelo]

Made the assumption the sensor was good as it was before the wire came off.
Not a guarantee it's good guess in my opinion.

[mrein3]

Originally Posted by saxart

This past summer I was driving down the road and started hearing a fast ticking noise from somewhere inside the cab. Long story short, it was the temp gauge. The needle was slamming from high to low over and over and over until I pulled over, popped the hood and found that the temp gauge wire had disconnected itself from the sensor and was grounding out on the engine block.

After reconnecting the wire, the gauge now reads very low even when the engine is up to operating temp.

picture snipped out

Is there a way to adjust these gauges so it reads at the right spot when the engine is warm, or do I need to replace the original gauge?

Given the proximity of that wire to the exhaust manifold and the fact that it was flopping around, I might look the wire over for a break or bare spot before procuring a new temp gauge and taking the time to install it.

[HO455]

I had the same thing happen to me. I didn't get to concerned as these aren't calibrated gauges. They are a reference to what is normal and if there is a problem the guage will still indicate a higher or lower than normal temperature condition.

That being said you can remove the needle from the post and reposition it to where you would like it to read when cold.

But in the big cycle of nature, mine fell off a second time, about two years after the first time, and reset itself nearly back where it was originally. So you could give that a try too.

[Mruss70]

On my gauge the needle came off and I couldn’t find it. My father in law had an extra so I put it in and the needle wouldn’t move off below cold. I traced the circuits and didn’t find any problems. I checked the temp sending unit and noted that the ohms were going down as the engine warmed up. 1700 ohms cold and 445 warm. After messing with it for a couple of days I was going to a guys house that works on these old trucks and the gauge started working. Now the gauge stays about 1/4 inch under half way. I did notice when I shut the truck off and restarted it the needle stays under the cold line until I rev the motor then it slowly climbs to 1/4 inch under half way.

[Accelo]

I have the specifications for the earlier sensors. I am not 100% sure it would apply but here goes.
@ 75 deg 700 ohms
@ 180 deg 140 ohms.

I mentioned, in an earlier post, you could correct a gauge by adding resistance. If you go this route it would only be correct when it was running at the temp the gauge was corrected for. It would be possible to overheat, and the gauge not read correctly,when the motor is overheating. It all depends on how much resistance one had to add to correct the gauge.

This is a bunch of monkeying around. Best to replace the broken gauge. Used ones are around and if time is money it would be the least inexpensive repair. However, I am not saying what your time is worth! "or do I need to replace the original gauge?" "Yes."

One could measure the ohms resistance and determine if the sensor is correct. a pot of water and a ohm meter is all that is required to confirm the sensor's function.
Good luck.